A. Sawicka-Grzelak

Biofilm production by clinical strains of Acinetobacter baumannii isolated from patients hospitalized in two tertiary care hospitals

Microbial biofilms are considered as virulence factors. During the present study, 34 clinical strains of Acinetobacter baumannii, isolated from patients hospitalized in two tertiary care hospitals, were examined for biofilm formation. These strains showed high variability in biofilm formation. Furthermore, no relation could be found between the ability of biofilm production and molecular type, carbapenem resistance, site of isolation of the clinical strains of A. baumannii and disease severity. Interestingly, in two cases an increase in biofilm formation could be detected in A. baumannii isolates cultured from the same patient upon prolonged hospitalization.

Urinary tract infections in the early posttransplant period after kidney transplantation: etiologic agents and their susceptibility.

OBJECTIVE Urinary tract infection (UTI) is among the most common infections in solid organ transplantation, especially in kidney transplantation. PATIENTS AND METHODS This study included 295 adult patients undergoing KTx between September 2001 and December 2007. All patients were followed prospectively for UTI during the first 4 weeks after surgery. Samples of urine were investigated by bacteriological cultures to identify microorganisms in accord with standard procedures. Susceptibility testing was performed using Clinical and Laboratory Standards Institute procedures. RESULTS Urine specimens (n=582) were obtained from 84.5% of 245 recipients during the first month after transplantation. Among the isolated bacterial strains (n=291), the most common were Gram-negative bacteria (56.4%) predominantly Serratia marcescens (32.3%) and Enterobacter cloacae (14.6%). Extended- spectrum beta-lactamase (ESBL+) strains were isolated in 52.5% of cases. Gram-positive bacteria comprised 35.7%; most commonly, high-level aminoglycoside resistant (HLAR; 87.8%) and vancomycin-resistant (VRE; 11%) Enterococci. There were fungal strains in 23 cases (7.9%). CONCLUSION Our study showed predominantly Gram-negative rods from the Enterobacteriaceae family comprising (84.8%) of Gram-negative isolates: 52.5% ESBL and resistant enterococci (87.5%) in Gram-positive isolates. The increased proportion of isolates of multi-drug-resistant bacterial agents which can cause severe UTIs may be due to our frequent use of ceftriaxone for perioperative bacterial prophylaxis.

A comparison of Api 20A vs MALDI-TOF MS for routine identification of clinically significant anaerobic bacterial strains to the species level.

Adequate identification of anaerobic bacteria still presents a challenge for laboratories conducting microbiological diagnostics. The aim of this study was to compare the use of Api 20A and MALDI-TOF MS techniques for identification of obligate anaerobes. The results indicate that MALDI-TOF MS ensures a rapid and accurate identification of the species isolated from patients.

A Threat of the Klebsiella Pneumoniae Carbapenemase–Producing Strains Among Transplant Recipients

BACKGROUND Infections due to Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae are associated with increased therapeutic failure and mortality. Our laboratory recognized several strains producing KPC, most of which originated from transplantation ward patients. MATERIALS AND METHODS All strains of K pneumoniae resistant to at least 1 carbapenem isolated in 2010 were examined for KPC production by disc diffusion and then verified by molecular methods. RESULTS All positive strains originated from 7 patients. Six of them were from transplantation wards. None of the KPC-producing strains was isolated from the patients blood. CONCLUSIONS A quick, accurate diagnosis of KPC-producing strains enabled immediate isolation of carriers or infected persons. Isolation prevented spread of dangerous strains among immunocompromised patients and reduced the possibility of serious infections.

Bacterial and fungal infections in the early post-transplantation period after liver transplantation: etiologic agents and their susceptibility.

OBJECTIVE It has been reported in many studies that one of the main factors influencing morbidity and mortality in patients receiving transplants is infection after transplantation. PATIENTS AND METHODS The study included 190 adult patients undergoing orthotopic liver transplantation (OLT) between September 2001 and December 2007. All the patients were followed prospectively for infections from the OLT date and during the first 4 weeks after surgery. Immunosuppression consisted of steroids and tacrolimus. Antimicrobial prophylaxis included piperacillin/tazobactam, fluconazole, and selective bowel decontamination (SBD) was performed. Samples of clinical materials were investigated for microbiological cultures. The micro-organisms were cultured and identified in accordance with standard bacteriological procedures. Susceptibility testing was performed using Clinical and Laboratory Standards Institute procedures. RESULTS From 190 OLT recipients, 2213 clinical samples were obtained for microbiological examination. Positive cultures were found in 27.2% (n = 603) of all samples tested; 1252 strains were collected. Gram-positive bacteria were found in 64.1% (n = 802), Gram-negative bacteria were found in 31.6% (n = 396), and fungal strains were isolated in 4.3% (n = 54). Surgical site specimens (n = 1031) were obtained from 190 recipients during the first month after transplantation. Positive cultures accounted for 29.2% (n = 301) of all samples tested. Among the isolated microbial strains (n = 677), most common were Gram-positive bacteria (73.7%; n = 499). Gram-negative bacteria comprised 25.1% (n = 170). There were fungal strains in 1.2% (n = 8). There were 539 urine specimens. Positive cultures accounted for 16.7% (n = 90) of those. Among the isolated microbial strains (n = 210), most common were Gram-negative bacteria (62.4%; n = 131). Gram-positive bacteria comprised 28.6% (n = 60) and fungi 9% (n = 19). There were 549 blood specimens. Positive cultures were found in 30.6% (n = 168) of all samples tested. Among the isolated microbial strains (n = 263), most common were Gram-positive bacteria in 72.3% (n = 190); Gram-negative bacteria were found in 26.2% (n = 69), and fungal strains were isolated in 1.5% (n = 4). There were 69 respiratory tract specimens. Positive cultures were found in 46.4% (n = 32) of all samples tested. Among the isolated microbial strains (n = 84), most common were Gram-positive bacteria (51.2%; n = 43); Gram-negative bacteria comprised 27.4% (n = 23) and fungi 21.4% (n = 18). CONCLUSIONS (1) Surgical site samples were predominated samples after LTx. (2) Our study showed Gram-positive bacteria were 64.1% (n = 802), Gram-negative bacteria, 31.6% (n = 396) and fungal strains isolated in 4.3% (n = 54). (3) The increased proportion of isolates of multi-drug-resistant bacterial strains (methicillin resistant coagulase negative Staphylococcus, vancomycin-resistant Enterococcus, high-level aminoglycoside resistance, and extended- spectrum β-lactamase). (4) These data indicate strict cooperation infection control procedures in these patients.

Surgical site infections in the early posttransplant period after simultaneous pancreas-kidney transplantation.

OBJECTIVE Urinary tract infection (UTI) is among the common infection in simultaneous pancreas-kidney transplantation (SPKT). PATIENTS AND METHODS The study included 26 adult patients undergoing SPKT between September 2001 and December 2006. All the patients were followed prospectively for UTI during the first 4 weeks after surgery. Urine samples were investigated for bacteriologic cultures. The micro-organisms were identified in accordance with standard bacteriologic procedures. Susceptibility testing was carried out using Clinical and Laboratory Standards Institute (CLSI) procedures. RESULTS Among 77 urine specimens obtained from all recipients during the first month, there were 30 isolated bacterial strains. The most common were Gram-positive bacteria (53.3%) with predominance of enterococci (75%) associated with high levels of aminoglycoside resistant strains (HLAR; 58.3%) and vancomycin-resistant strains (VRE; 25%). Gram-negative bacteria were detected in 46.7% of positive cultures. CONCLUSIONS In our study, enterococci predominated as 75% of Gram-positive isolates. The increased proportion of multi-drug-resistant bacteria, which can caused severe UTI in patients after SPKT, may be due to the frequent use of prophylaxis of bacterial infections in patients.

Etiologic agents of bacteremia in the early period after simultaneous pancreas-kidney transplantation.

BACKGROUND Bacteremia is among the known complications in simultaneous pancreas-kidney transplantation (SPKT). This study evaluated the frequency of microbial isolates and their susceptibility profiles among cultures of clinical samples obtained from blood and from the tips of blood vessel catheters of 26 SPKT recipients suspected of bacteremia in the early posttransplant period. PATIENTS AND METHODS Data on microbiologic blood cultures of 26 adult patients undergoing SPKT were collected prospectively from 2001 to the end of 2006. The isolation and identification of cultured microorganisms were performed according to standard microbiological procedures and commercially available tests. The susceptibility of the strains to antibacterial agents was established by the Clinical and Laboratory Standards Institute guidelines. RESULTS All patients were followed prospectively for the first 4 weeks after surgery. Among 66 clinical samples, there were 23 microbial isolates from blood samples of 17 recipients and catheter tips of 12 recipients. The most common isolates were Gram-positive bacteria (73.9%) with domination of staphylococci (64.7%) and MRCNS strains (81.8%). Gram-negative bacteria comprised 17.4% of positive cultures, whereas yeast-like fungi, 8.7% with a predominance of Candida glabrata. CONCLUSION Our study showed predominately Gram-positive bacteria in 73.9% of isolates. The increased proportion of multi-drug-resistant bacteria and fungi to antimicrobial agents may be due to the frequent use of these agents for prophylaxis of bacterial infections in patients.

CTX-M and TEM as Predominant Types of Extended Spectrum β-Lactamases Among Serratia marcescens Isolated From Solid Organ Recipients

BACKGROUND Serratia marcescens is an important pathogen in hospital infections since organisms resistant to multiple antimicrobials pose a special threat particularly among transplant patients. The aim of this work was to assess the number of strains producing beta-lactamases with extended spectrum (ESBL) among S. marcescens isolated from our patients. MATERIALS AND METHODS We investigated S. marcescens isolated from 2005 to 2008 for ESBL. The phenotype methods were applied and additionally we chose strains for polymerase chain reactions using primers for the most popular types of ESBL. RESULTS Over the investigated time, 257 patients were infected with S. marcescens with 188 (73%) displaying an ESBL-positive phenotype. A Molecular analysis showed that most of them produced both CTX-M and TEM beta-lactamases. In the last year, the percentage of ESBL-producing strains decreased, but also in the last year, we isolated S. marcescens resistant to carbapenems from three patients. CONCLUSIONS The CTX-M type of ESBL predominated among ESBLs produced by strains of S. marcescens. The appearance of strains resistant to carbapenems is alarming.

Urinary tract infections in the early posttransplant period after liver transplantation: etiologic agents and their susceptibility.

BACKGROUND We performed an analysis of etiologic agents for urinary tract infections in the early posttransplant period after orthotopic liver transplantation (OLT) in adult recipients. PATIENTS AND METHODS The study covered the first 4 weeks after OLT of 190 patients from September 2001 to the end of 2007. Immunosuppression consisted of steroids and tacrolimus. Antimicrobial prophylaxis was piperacillin/tazobactam, fluconazole, and SBD. Urine samples were cultured to identify microorganisms in accord with standard microbiological procedures and to test susceptibility using Clinical Laboratory and Standards Institute guidelines. RESULTS Urine specimens (n=539) examined from 185 recipients (97.4%) showed 210 microbial strains. The most common were Gram-negative (n=131; 62.4%) with predominance of Escherichia coli (28.2%), Enterobacter cloacae (19.1%), and Acinetobacter baumannii (11.4%). Extended-spectrum β- lactamases (ESBL(+)) strains were isolated in 38.5% of cases. Gram-positive bacteria comprised 28.6% (n=60): The most common strains were enterococci (85% including HLAR 80.4% and VRE 17.6%] and staphylococci 11.8% [MRSA/MRCNS; 100%]. There were 19 (9%) fungal strains. CONCLUSIONS In general, the identification in urine samples of multi-drug-resistant bacterial and fungal strains in patients after OLT such as ESBL(+) 38.5%; HLAR 80.4%; VRE 17.6%; and MRSA/MRCNS 100% requires better infection control.

Specific Character of Anaerobic Bacterial Infections in Patients Treated in Transplantation Wards at One of the Clinical Hospitals in Warsaw

Immunocompromised patients and patients undergoing invasive procedures are predisposed to bacterial infections, due to the possibility of micro-organism translocation from their physiological habitat. Infectious complications may occur both in the early and late post-transplantation periods. The purpose of this study was to evaluate the proportion as well as susceptibility profiles of obligatory anaerobes in the etiology of infections in patients hospitalized at transplantation wards of a large clinical hospital in Warsaw. A total of 104 strains of obligatory anaerobes derived from patients hospitalized in two transplantation clinics at a clinical hospital in Warsaw were evaluated. The strains were isolated from 87 clinical samples collected from 84 patients of two transplantation wards between 2007 and 2012. A total of 104 obligatory anaerobic bacterial strains were isolated and identified, with Gram-positive and Gram-negative bacteria constituting 60.6% and 39.4% of the isolates, respectively. Almost exclusively non-spore-forming anaerobes were detected in evaluated samples. The present study showed all isolated Gram-positive bacteria to be susceptible to ß-lactam antibiotics. Metronidazole-resistant bacteria were found among the genera Propionibacterium and Actinomyces. All Gram-negative rods were susceptible to imipenem and metronidazole. Among them, Bacteroides spp. and Parabacteroides distasonis showed resistance to penicillin G (100%). Because of their pathogenicity and altered antibiotic susceptibility profiles, the bacteria of the genera Bacteroides and Parabacteroides are of greatest clinical importance. Approximately 25% of isolates exhibit also resistance to clindamycin. Because of the growing rates of clindamycin resistance, the role of metronidazole in the treatment of Bacteroides spp. is of increasing importance.